The present invention relates in general to automotive heating, ventilating, and air conditioning (HVAC) systems, and, more specifically, to a system and method for coordinating multiple heating and cooling devices to provide thermal comfort to vehicle occupants in a manner that optimizes energy expenditure.
Thermal comfort has been provided in conventional automotive vehicles using a forced-air central HVAC system. Supplemental devices such as heated seats, cooled seats, heated steering wheels, or partitioned climate zones have become available for increasing comfort.
Even when included as standard equipment, control of supplemental devices has not been integrated with the main HVAC system. Thus, the user must manually attend to each standalone device in an attempt to balance the overall comfort provided by all the devices working together. Besides causing undesirable distraction, it is unlikely that the devices can all be manually set such that the most effective operation is obtained.
Energy usage in the vehicle to obtain a comfortable climate is becoming an important issue. As one consequence of creating vehicles with higher energy efficiency, total energy available for the HVAC system has become more restricted. In vehicles with internal combustion engines, the engines have become smaller and more thermally efficient. In full electric and hybrid electric vehicles, electrically-driven heaters are required as heat sources. Battery life and vehicle range may be severely compromised in cold weather when electrical heating is employed. Likewise, compressor loads in an AC system in an electric vehicle will consume a greater portion of the vehicle energy budget as powertrains become more efficient.
Providing thermal comfort to vehicle occupants requires manufacturers to design comfort systems that integrate key vehicle systems with intelligent controls to take advantage of different vehicle usage patterns. Minimizing vehicle thermal loads and HVAC energy usage and taking advantage of physiological sensations in ways that reduce energy usage are essential to maximizing fuel economy while meeting customer comfort expectations.